Gaga, who has been subpoenaed in the case, has been an outspoken supporter of Kesha during Kesha's legal battle against Luke over claims he drugged, raped, and emotionally abused her.

Luke’s lawyers claim Gaga joined Kesha’s “smear campaign” against the producer and “spread negative messages,” including a statement urging Sony Music to cut ties with Luke, according to court docs.

“Dr. Luke's counsel served a subpoena on Lady Gaga because she has relevant information regarding, among other things, false statements about Dr. Luke made to her by Kesha,” Luke’s lawyers wrote in a statement. “This motion has become necessary because Dr. Luke's counsel has not been able to obtain, despite repeated request, a deposition date from Lady Gaga."